The deepest ocean trench in the world is the Mariana Trench, located in the western Pacific Ocean. It is part of a series of trenches on the ocean floor in the western Pacific. It extends from the Sulawesi Islands in the north to near Yap Island in the southwest, with a total length of approximately 2,550 kilometers, an average width of 69 kilometers, and most of its water depth exceeding 8,000 meters. The deepest point is the Challenger Deep, with a depth of 11,034 meters, making it the lowest point on Earth.

The water depth at different locations in the Mariana Trench shows significant segmentation. Generally, the water depth increases gradually from north to south, with the trench bottom depth rising from 6,000-7,000 meters to over 9,000 meters. It is completely dark here, with low water temperatures, low oxygen levels, and scarce food resources. The water pressure is immense, making it one of the most extreme environments on Earth. However, scientists have still discovered various forms of life here, including fish, single-celled organisms, and alkaliphilic bacteria.